What do you have your flight speed set to? That will likely affect things...
Map Pilot adjusts the speed according the the along track overlap setting and the SD Card write speed. If you have the SD card write speed set to 2 seconds between images that will allow you to fly the fastest possible.
The FOV of the camera matters too. A 94 degree Phantom 3 will cover ground faster than a narrower FOV Mavic.
Map Pilot accounts for all of this automatically and doesn't let you fly faster than your camera/sdcard can handle.